ROTARY SCREENING DEVICE

Description

[0001] The present invention relates to a rotary screening device for separating unwanted solid matter from sea or fresh water. It is particularly directed towards the removal of such matter floating at indeterminate depths, such as sewage, weeds, fish, jelly fish and tar balls.

[0002] Solid matter such as weeds and jelly fish floating or submerged in water can be a considerable nuisance when the water is to be used for a special purpose for example sea water in a desalination plant, or fresh water for cooling in manufacturing plant process.

[0003] The water intake ducts used for such purposes are usually provided with filters for screening unwanted solid matter before the water reaches its destination.

[0004] However, the use of filters does not entirely solve the problem because certain solid matter is able on occasions to get past the filters and in the case of tar balls for example the filters themselves merely become blocked.

[0005] Further algae and such other weed growth tend to block intake filters in certain parts of the world.

[0006] As representative prior art, a screening assembly is disclosed in US-A-4 303 508 having a rotatable screening drum which separates out unwanted matter from suspensions of cellulosit fibre material such that the clean suspension passes to an outlet from the interior of the screening drum. Scraper elements are positioned in the annular slots forming the screening element of the drum to keep these slots from becoming blocked.

SUMMARY OF THE INVENTION

[0007] It is an object of the present invention to provide a screening device which is able to remove unwanted solid matter from water subsequently to be used for a special purpose, inlcuding floating solid matter and matter such as tar balls which move at indeterminate depths beneath a water surface.

[0008] According to the invention there is provided a rotary screening device for separating unwanted solid matter such as weeds, fish and tar balls from a body of water comprising a rotatable support body provided with screening passageways for screening unwanted solid matter from the water as the support body is rotated therein a scraper element arranged to maintain the passageways clear of unwanted solid matter during screening, and outlet means for discharging the screened water from the interior of the support body characterised in that the support body is provided with a plurality of rows of peripheral teeth for collecting unwanted solid matter from the water during rotation of the support body, said scraper element engaging spaced outwardly facing annular surfaces provided between each of the peripheral rows of teeth to remove unwanted matter collected on the teeth and said annular surfaces for discharge to a collection zone, said screening passageways being formed by the spacing between said annular surfaces for radially inward passage of water cleaned of said unwanted solid matter, to the interior of said support body and then through said outlet means.

[0009] Preferably the peripheral teeth are formed on individual annular elements the central apertures of which permit them to be mounted on the support body in a stacked array. The periphery of each annular aperture may then be provided with a series of spaced notches for engagement with a series of axially extending rods of the support body defining a hollow interior thereof.

[0010] The support rods are preferably held between two transversely extending end plates to complete the support body for the annular elements of the device, one of the end plates having apertures forming an outlet for cleaned water from the hollow interior of the support body.

[0011] The sides of each of the annular elements are provided with annular flanges having protuberances which serve to separate the annular flanges in the stacked array thereby providing annular slits leading to the hollow interior of the support body, the annular flanges providing the annular surface for the scraper elements which occupy the space provided between the adjacent annular elements in the stacked array.

[0012] Other features and advantages of the present invention will become apparent from the more detailed disclosure which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings wherein:

Fig 1 is a side view showing a single toothed disc and cooperating scraper element of a rotatory screening device according to an embodiment of the invention;

Fig 2 is a front view of a stacked assembly of the toothed annular elements shown in Fig 1;

Fig 3 is a perspective view of a carrier assembly for the annular elements shown in Fig 1;

Fig 4 is an enlarged view illustrating an engagement of the scraper elements of the device as shown in Figs 1 and 2 engaging the annular clean water slits formed between adjacent annular elements in the stacked assembly.

BEST MODES OF CARRYING OUT THE INVENTION

[0014] The rotary screening device according to an embodiment of the invention as shown in Figs 1 to 4 comprises a series of annular elements 1 adjacently positioned in stacked assembly, see Fig 2, on a rotatable support body 2. Each annular element 1 is provided with a peripheral row of teeth 3.

[0015] The sides of each annular element 1 are provided with circular flanges 6 of equal radius.

[0016] The flanges 6, see Fig 2, are separated from one another by a small gap, the gap being maintained by means of protuberances 7, formed on one of the facing flanges 6, the thus formed gap providing an annular slit 8 communicating with the interior of the rotatable support body 2.

[0017] The support body 2 is composed of axially extending parallel rods 9 the ends of which are fastened to the peripheral edge of two transversely extending circular end plates 10 and 11 the plate 11 being of large diameter such that a semi-circular section of each rod sits proud of the circular periphery of the end plate 10.

[0018] The periphery of the circular apertures 4 in each annular elements 1 is provided with a series of notches 5 whose profile corresponds to the semi-circular section of the rods 9, sitting proud of the periphery of the end plate 10.

[0019] By this means each annular element 1 may be slidably mounted on the support body 2 over the end plate 10, by means of the notches 5 engaging the semi-circular sections of the rods 9 thereby to key the annular elements to the support body 2.

[0020] The annular elements 1 are held together on the support body 2, between the larger end plate 11, and a closure plate 10' attached to the plate 10, thereby to complete the confinement of the stacked array.

[0021] The support body 2 has an axial shaft 12 which may be journalled for rotation in bearings (not shown) at one or both ends depending upon whether it is to be used with the shaft vertical or in a horizontal position, and by means of a suitable motor drive (not shown).

[0022] One end of a pivotally mounted scraper element 13 engages the surface of the flanges 6 between the annular elements 1 as the support body rotates. Each scraper element 13 has a width which corresponds substantially to the width between the adjacent annular elements 1 as shown, and is provided with an extension piece 14 on its lower side which engages the annular slits 8 between the annular flanges 6.

[0023] Each scraper element 13 is urged to its scraping position by means of a spring 15.

[0024] The teeth on each annular rotatable element shown more particularly in Fig 4 have operative faces forming involute curves to a base circle to which the face of the scraper element 13 is tangential.

[0025] The attack angle between a tooth and the face of a scraper element is 90° throughout the engagement zone although other constant attack angle arrangements may be designed as disclosed for example in UK Patent 2190605 (WO-A-8604268).

[0026] To complete the assembly as shown in Fig 3 a metal plate 16 extends across the assembly such that as the teeth rotate in the direction of the arrow unwanted solid matter collected thereon is thrown over the plate 16 as is matter scraped from the surface formed by the annular flanges 6 under the action of the scraper elements, thereafter to be delivered to a discharge zone (not shown).

[0027] Clean water, that is water from which has been separated unwanted solid matter, passes through the annular passageways or slits 8 to the interior of the support body from whence is may be drawn off through apertures 17 in the larger end plate 11 by suitable suction means to a snugly fitting stationary discharge duct (not shown).

[0028] Figs 5 and 6 illustrate by way of example, a specific use of the device described above in the treatment of sewage.

[0029] The rotary screening device of the arrangement shown in Fig 2, is shown in Figs 5 and 6 positioned in a channel 18 carrying water contaminated with sewage effluent and flowing in the direction F such that the rotating teeth 3 encounter the entire flow of water arriving from the upstream direction.

[0030] In the illustration shown rotation of the teeth 3 is such that the teeth 3 are ascending relative to the arriving flow as shown by arrow A thereby to capture solid matter in the sewage and carry it above the level of the water L in the confined flow, where it is stripped from the teeth 3 by the scraper elements 13, and delivered to a laterally extending conveyor 19 for suitable disposal.

[0031] Cleaned water passes through the slits 8 between the annular elements 1 of the stacked assembly and downstream of the confined water flow.

[0032] To ensure that the slits 8 do not themselves become clogged by matter which might pass through the slits 8, and be unable to escape from inside the stack, the interior of the support body 2, see Fig 6, is provided with stationary deflectors 20 which direct the cleaned water to the apertures 17 in the end plate 11, see Fig 3, and or similar apertures provided in the end plates 10 and 10'.

[0033] To provide for sideways deflection of the cleaned water from the interior of the stacked assembly to the downstream side of the screening device, the channel 18 is provided with a widened section 21 as shown.

[0034] In the application shown in Fig 5 and 6 the teeth 3 operate over a small distance above the water surface.

[0035] Operation in a totally submerged position is possible to deal entirely with submerged solid matter such as tar balls, and preferably in a water current which has been flowing quiescently for a sufficient time to allow fine grits such as sand to have been gravitationally rejected.

[0036] A large installation may comprise a number of rotary screening devices suspended from a bridge carrying the main common driving means.

[0037] To cater for an occurence where tar balls are encountered in large quantities it is envisaged that a trip switch would be included in the operating drive which would actuate upon a large increase in driving torque consequent upon the drag effect produced by the viscosity of the tar.

Claims

1. A rotary screening device for separating unwanted solid matter such as weeds, fish and tar balls from a body of water comprising a rotatable support body (2) provided with screening passageways (8) for screening unwanted solid matter from the water as the support body is rotated therein, a scraper element arranged to maintain the passageways clear of unwanted solid matter during screening, and outlet means for discharging the screened water from the interior of the support body (2) characterised in that the support body is provided with a plurality of rows of peripheral teeth (3) for collecting said unwanted solid matter from the water during rotation of the support body (2), said scraper element (13) engaging spaced outwardly facing annular surfaces provided between each of the peripheral rows of teeth (3) to remove unwanted matter collected on the teeth (3) and said annular surfaces for discharge to a collection zone, said screening passageways (8) being formed by the spacing between said annular surfaces for radially inward passage of water cleaned of said unwanted solid matter, to the interior of said support body (2) and then through said outlet means.

2. A rotary screening device as claimed in claim 1 wherein said peripheral teeth (3) are formed on individual annular elements (1) arranged on said support body (2).

3. A rotary screening device as claimed in claim 2 wherein the support body (2) is formed of an annular array of axially extending rods (9) the ends of which are attached to transversely extending end closure plates (11), said annular elements (1) being mounted around said rods (9).

4. A rotary screening device as claimed in claim 3 wherein the annular elements (1) have facing annular side flanges (6) with protuberances (7) formed on one of the side flanges of a facing pair of side flanges to form a series of annular gaps (8) between the side flanges (6) which provide said access passageway means (8) for passage of cleaned water to the interior of the support body (2).

5. A rotary screening device as claimed in claim 4 wherein said discharge means is in the form of apertures (17) provided in at least one of the end plates (11) for conveying cleaned water from the interior of the support means (2) to a stationary duct in communication with said interior.

6. A rotary screening device as claimed in claim 5 wherein each pair of said facing annular side flanges (6) form said annular surfaces which are engaged by a said scraper element (13), each said scraper element (13) having a projecting piece (14) which enters the annular gaps (8) formed between said annular flanges (6).

7. A rotary screening device as claimed in claims 5 and 6 and having internal deflectos (20) positioned in the interior of said support body (2) and which are capable of being held stationary with respect to rotation of the support body (2) thereby to direct clean water entering the slits from an upstream direction to the apertures (17) formed int he end plates (11).

Ansprüche

1. Eine rotierende Siebvorrichtung zum Abtrennen von unerwünschten Feststoffen, wie beispielsweise Unkraut oder Pflanzen, Fische und Teerbrocken aus einem Wasserkörper, mit einem rotierenden Trägerkörper (2) mit siebartigen Durchlässen (8) zum Abscheiden von unerwünschten Fest- oder fremdstoffen aus dem Wasser, wenn der Trägerkörper in diesem rotiert wird, mit einem Schaberelement, welches so angeordnet ist, um die Durchlässe von unerwünschten Feststoffen während des Siebens freizuhalten, sowie mit Auslaßmitteln zur Abgabe des gesiebten oder gefilterten Wassers aus dem Inneren des Trägerkörpers (2), dadurch gekennzeichnet, daß der Trägerkörper mit einer Vielzahl von Reihen von peripheren Zähnen (3) versehen ist, und zwar zur Aufnahme bzw. zum Sammeln der unerwünschten Feststoffe aus dem Wasser während der Rotation des Trägerkörpers (2), wobei das Schaberelement (13) mit beabstandeten, nach außen weisenden Ringflächen zusammenwirkt, die zwischen jeder der peripheren Reihen von Zähnen (3) vorgesehen sind, um an den Zähnen sowie an den erwähnten Ringflächen gesammeltes Material zu entfernen, und zwar für eine Abgabe an eine Sammelzone, und daß die siebartigen Durchlässe (8) von dem Abstand zwischen den Ringflächen gebildet sind, und zwar für einen Durchtritt des von den unerwünschten Feststoffen gereinigten Wassers radial nach innen in das Innere des Trägerkörpers (2) und dann durch die Auslaßmittel.

2. Eine rotierende Siebvorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die peripheren Zähne (3) an individuellen ringförmigen Elementen (1) gebildet sind, die am Trägerkörper (2) vorgesehen sind.

3. Eine rotierende Siebvorrichtung nach Anspruch 2, dadurch gekennzeichnet, daß der Trägerkörper (2) von einer ringförmigen Anordnung von sich in Achsrichtung erstreckenden Stäben (9) gebildet ist, deren Enden mit quer angeordneten oder stirnseitigen Abschlußplatten (11) verbunden sind, wobei die ringförmigen Elemente (1) um die erwähnten Stäbe oder Stangen (9) befestigt sind.

4. Eine rotierende Siebvorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß die ringförmigen Elemente einander zugewandte ringförmige Seitenflansche (6) mit Vorsprüngen (7) aufweisen, die jeweils an einem Seitenflansch der Paaren voneinander zugewandten Seitenflanschen vorgesehen sind, um eine Reihe von ringförmigen Spalten (8) zwischen den Seitenflanschen (6) zu bilden, die die erwähnten Durchlaßmittel (8) für den Durchlaß des gereinigten Wassers in das Innere des Trägerkörpers (2) bilden.

5. Eine rotierende Siebvorrichtung nach Anspruch 4, dadurch gekennzeichnet, daß die Durchlaßmittel die Form von Öffnungen (17) aufweisen, die in wenigstens einer der Stirnplatten (11) vorgesehen sind, um das gereinigte Wasser aus dem Inneren der Trägermittel (2) in eine mit dem Inneren in Verbindung stehende stationäre Leitung zu leiten.

6. Eine rotierende Siebvorrichtung nach Anspruch 5, dadurch gekennzeichnet, daß jedes Paar der erwähnten, einander zugewandten ringförmigen Seitenflansche (6) die erwähnten Ringflächen bildet, mit denen das erwähnte Abstreifelement (13) in Verbindung steht, wobei jedes Abstreifelement (13) einen vorstehenden Abschnitt (14) aufweist, der in die Ringspalte (8) hineinreicht, die zwischen den erwähnten ringförmigen Flanschen (6) gebildet ist.

7. Eine rotierende Siebvorrichtung nach Anspruch 5 und 6 und mit inneren Ablenkelementen (20), die im Inneren des Trägerkörpers (2) vorgesehen sind und die in bezug auf die Drehbewegung des Trägerkörpers (2) stationär gehalten werden können, um hierbei das gereinigte Wasser, welches in die Schlitze von stromaufwärts eintritt, an die in den Stirnplatten (11) vorgesehenen Öffnungen zu leiten.

Revendications

1. Dispositif de filtrage rotatif pour séparer des matières solides indésirables telles que des herbes, des poissons et des particules de goudrons d'une masse d'eau comprenant un support principal rotatif (2) comportant des passages de filtrage (8) pour séparer les matières solides indésirables de l'eau lorsque le support est entraîné en rotation, un élément racloir agencé pour maintenir les passages dégagés des matières solides indésirables pendant le filtrage et des moyens de sortie pour vider l'eau filtrée de l'intérieur du support (2), caractérisé en ce que le support principal porte une pluralité de rangées de dents périphériques (3) afin de collecter lesdites matières solides indésirables contenues dans l'eau pendant la rotation du support (2), ledit élément racloir (13) venant en prise avec des surfaces annulaires espacées orientées vers l'extérieur formées entre chacune des rangées périphériques de dents (3) pour éliminer les matières indésirables accumulées sur les dents (3) et sur lesdites surfaces annulaires afin de les évacuer vers une zone de collecte, lesdits passages de filtrage (8) étant constitués par l'écart entre lesdites surfaces annulaires pour faire passer radialement vers l'intérieur l'eau débarrassée desdites particules solides indésirables, en direction de l'intérieur dudit support (2) et ensuite à travers lesdits moyens de sorties.

2. Dispositif de filtrage rotatif selon la revendication 1, dans lequel lesdites dents périphériques (3) sont formées sur des éléments annulaires individuels (1) installés sur ledit support (2).

3. Dispositif de filtrage rotatif selon la revendication 2, dans lequel le support principal (2) est constitué d'un réseau annulaire de tiges (9) orientées dans la direction axiale dont les extrémités sont reliées à des places de fermeture d'extrémité orientées transversalement (11), lesdits éléments annulaires (1) étant montés autour desdites tiges (9).

4. Dispositif rotatif de filtrage selon la revendication 3, dans lequel les éléments annulaires (1) sont en face de brides latérales annulaires (6) avec des protubérances (7) formées sur l'une des brides latérales d'une paire de brides latérales orientées face à face pour constituer une série d'espaces annulaires (8) entre les brides latérales (6), lesquels donnent accès auxdit moyens de passage (8) pour faire circuler l'eau filtrée vers l'intérieur du support principal (2).

5. Dispositif rotatif de filtrage selon la revendication 4, dans lequel lesdits moyens de sortie prennent la forme d'ouvertures (17) formées dans au moins une des plaques d'extrémité (11) pour acheminer l'eau filtrée de l'intérieur du moyen support principal (2) vers un conduit fixe en communication avec ledit intérieur.

6. Dispositif de filtrage rotatif selon la revendication 5, dans lequel chaque paire de brides latérales (6) orientées face à face constitue lesdites surfaces annulaires avec lesquelles vient en prise un élément racloir (13), chaque élément racloir (13) portant une pièce en saillie (14) qui pénètre dans les espaces annulaires (8) formés entre lesdites brides annulaires (6).

7. Dispositif de filtrage rotatif selon les revendications 5 et 6, comportant des déflecteurs internes (20) installés à l'intérieur dudit support principal (2) et capables d'être maintenus fixes par rapport à la rotation du support principal (2) de manière à diriger l'eau propre pénétrant dans las fentes depuis une direction amont jusqu'aux ouvertures (17) formées dans les plaques d'extrémité (11).

Drawing